// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

#include <spdlog/common.h>
#include <spdlog/details/circular_q.h>
#include <spdlog/details/file_helper.h>
#include <spdlog/details/null_mutex.h>
#include <spdlog/details/os.h>
#include <spdlog/details/synchronous_factory.h>
#include <spdlog/fmt/chrono.h>
#include <spdlog/fmt/fmt.h>
#include <spdlog/sinks/base_sink.h>

#include <chrono>
#include <cstdio>
#include <iomanip>
#include <mutex>
#include <sstream>
#include <string>

namespace spdlog {
namespace sinks {

    /*
 * Generator of daily log file names in format basename.YYYY-MM-DD.ext
 */
    struct daily_filename_calculator
    {
        // Create filename for the form basename.YYYY-MM-DD
        static filename_t calc_filename(const filename_t& filename, const tm& now_tm)
        {
            filename_t basename, ext;
            std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
            return fmt_lib::format(
                SPDLOG_FMT_STRING(SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}{}")), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday, ext);
        }
    };

    /*
 * Generator of daily log file names with strftime format.
 * Usages:
 *    auto sink =
 * std::make_shared<spdlog::sinks::daily_file_format_sink_mt>("myapp-%Y-%m-%d:%H:%M:%S.log", hour,
 * minute);" auto logger = spdlog::daily_logger_format_mt("loggername, "myapp-%Y-%m-%d:%X.log",
 * hour,  minute)"
 *
 */
    struct daily_filename_format_calculator
    {
        static filename_t calc_filename(const filename_t& file_path, const tm& now_tm)
        {
#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
            std::wstringstream stream;
#else
            std::stringstream stream;
#endif
            stream << std::put_time(&now_tm, file_path.c_str());
            return stream.str();
        }
    };

    /*
 * Rotating file sink based on date.
 * If truncate != false , the created file will be truncated.
 * If max_files > 0, retain only the last max_files and delete previous.
 */
    template <typename Mutex, typename FileNameCalc = daily_filename_calculator> class daily_file_sink final : public base_sink<Mutex>
    {
    public:
        // create daily file sink which rotates on given time
        daily_file_sink(filename_t base_filename,
                        int rotation_hour,
                        int rotation_minute,
                        bool truncate = false,
                        uint16_t max_files = 0,
                        const file_event_handlers& event_handlers = {})
            : base_filename_(std::move(base_filename)), rotation_h_(rotation_hour), rotation_m_(rotation_minute), file_helper_{event_handlers},
              truncate_(truncate), max_files_(max_files), filenames_q_()
        {
            if (rotation_hour < 0 || rotation_hour > 23 || rotation_minute < 0 || rotation_minute > 59)
            {
                throw_spdlog_ex("daily_file_sink: Invalid rotation time in ctor");
            }

            auto now = log_clock::now();
            auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
            file_helper_.open(filename, truncate_);
            rotation_tp_ = next_rotation_tp_();

            if (max_files_ > 0)
            {
                init_filenames_q_();
            }
        }

        filename_t filename()
        {
            std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
            return file_helper_.filename();
        }

    protected:
        void sink_it_(const details::log_msg& msg) override
        {
            auto time = msg.time;
            bool should_rotate = time >= rotation_tp_;
            if (should_rotate)
            {
                auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(time));
                file_helper_.open(filename, truncate_);
                rotation_tp_ = next_rotation_tp_();
            }
            memory_buf_t formatted;
            base_sink<Mutex>::formatter_->format(msg, formatted);
            file_helper_.write(formatted);

            // Do the cleaning only at the end because it might throw on failure.
            if (should_rotate && max_files_ > 0)
            {
                delete_old_();
            }
        }

        void flush_() override { file_helper_.flush(); }

    private:
        void init_filenames_q_()
        {
            using details::os::path_exists;

            filenames_q_ = details::circular_q<filename_t>(static_cast<size_t>(max_files_));
            std::vector<filename_t> filenames;
            auto now = log_clock::now();
            while (filenames.size() < max_files_)
            {
                auto filename = FileNameCalc::calc_filename(base_filename_, now_tm(now));
                if (!path_exists(filename))
                {
                    break;
                }
                filenames.emplace_back(filename);
                now -= std::chrono::hours(24);
            }
            for (auto iter = filenames.rbegin(); iter != filenames.rend(); ++iter) { filenames_q_.push_back(std::move(*iter)); }
        }

        tm now_tm(log_clock::time_point tp)
        {
            time_t tnow = log_clock::to_time_t(tp);
            return spdlog::details::os::localtime(tnow);
        }

        log_clock::time_point next_rotation_tp_()
        {
            auto now = log_clock::now();
            tm date = now_tm(now);
            date.tm_hour = rotation_h_;
            date.tm_min = rotation_m_;
            date.tm_sec = 0;
            auto rotation_time = log_clock::from_time_t(std::mktime(&date));
            if (rotation_time > now)
            {
                return rotation_time;
            }
            return {rotation_time + std::chrono::hours(24)};
        }

        // Delete the file N rotations ago.
        // Throw spdlog_ex on failure to delete the old file.
        void delete_old_()
        {
            using details::os::filename_to_str;
            using details::os::remove_if_exists;

            filename_t current_file = file_helper_.filename();
            if (filenames_q_.full())
            {
                auto old_filename = std::move(filenames_q_.front());
                filenames_q_.pop_front();
                bool ok = remove_if_exists(old_filename) == 0;
                if (!ok)
                {
                    filenames_q_.push_back(std::move(current_file));
                    throw_spdlog_ex("Failed removing daily file " + filename_to_str(old_filename), errno);
                }
            }
            filenames_q_.push_back(std::move(current_file));
        }

        filename_t base_filename_;
        int rotation_h_;
        int rotation_m_;
        log_clock::time_point rotation_tp_;
        details::file_helper file_helper_;
        bool truncate_;
        uint16_t max_files_;
        details::circular_q<filename_t> filenames_q_;
    };

    using daily_file_sink_mt = daily_file_sink<std::mutex>;
    using daily_file_sink_st = daily_file_sink<details::null_mutex>;
    using daily_file_format_sink_mt = daily_file_sink<std::mutex, daily_filename_format_calculator>;
    using daily_file_format_sink_st = daily_file_sink<details::null_mutex, daily_filename_format_calculator>;

}  // namespace sinks

//
// factory functions
//
template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> daily_logger_mt(const std::string& logger_name,
                                               const filename_t& filename,
                                               int hour = 0,
                                               int minute = 0,
                                               bool truncate = false,
                                               uint16_t max_files = 0,
                                               const file_event_handlers& event_handlers = {})
{
    return Factory::template create<sinks::daily_file_sink_mt>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
}

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> daily_logger_format_mt(const std::string& logger_name,
                                                      const filename_t& filename,
                                                      int hour = 0,
                                                      int minute = 0,
                                                      bool truncate = false,
                                                      uint16_t max_files = 0,
                                                      const file_event_handlers& event_handlers = {})
{
    return Factory::template create<sinks::daily_file_format_sink_mt>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
}

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> daily_logger_st(const std::string& logger_name,
                                               const filename_t& filename,
                                               int hour = 0,
                                               int minute = 0,
                                               bool truncate = false,
                                               uint16_t max_files = 0,
                                               const file_event_handlers& event_handlers = {})
{
    return Factory::template create<sinks::daily_file_sink_st>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
}

template <typename Factory = spdlog::synchronous_factory>
inline std::shared_ptr<logger> daily_logger_format_st(const std::string& logger_name,
                                                      const filename_t& filename,
                                                      int hour = 0,
                                                      int minute = 0,
                                                      bool truncate = false,
                                                      uint16_t max_files = 0,
                                                      const file_event_handlers& event_handlers = {})
{
    return Factory::template create<sinks::daily_file_format_sink_st>(logger_name, filename, hour, minute, truncate, max_files, event_handlers);
}
}  // namespace spdlog
